Apparatus for making sheet metal files



Feb. 12, 1963 R. E. STUTZKE ETAL 3,077,126

APPARATUS FOR MAKING SHEET METAL FILES Original Filed June 20', 1958 4Shee ts-Sheet 1 lNV NTORS'. fgumj C01 Feb. 12, 1963 R. E. STUTZKE ETAL3,077,126

APPARATUS FOR MAKING SHEET METAL FILES 4 Sheets-Sheet 2 Original FiledJune 20, 1958 Fe 1963 R. E. STUTZKE ETAL 3,077,126

FILES 1963 R. STUTZKE ETAL 3,077,125

APPARATUS FOR MAKING SHEET METAL FILES Original Filed June 20, 1958 4Sheets-Sheet 4 [and 7 claims. (Ct. id-i2) The present invention relatesto sheet metal files, and particularly, to improved apparatus for makingthe same.

This application is a division of our co-pending application, Serial No.743,286, filed June 29, 1958.

The art of making files, rasps, planes and like tools for removal ofrelatively small amounts of material in the wood and metal worle'ngindustries in an old art and replete with suggestions for making suchtools or the cutting blades thereof from sheet metal blanks. In the fileart, for example, it has been proposed to bend slats or louvers out ofthe plane of a sheet metal blank to afford a tool having a plurality ofcutting teeth and slit-like openings between the teeth for chipclearance, which openings render the tool self-cleaning. In oneproposal, the slats or louvers, in order to form cutting teeth, are bentout of the blank at a relatively low angle of inclination, suitable as aclearance angle, and the frontal edge of each slat or louver is groundoff to a suitable cutting angle. Another proposal has been to bend theslats or louvers to a relatively large angle of inclination, at whichthe surfaces of the slats initially constituting the faces of the blankdefine a suitable cutting angle, and then grind oil the outer edgeportion of each slat to a suitable clearance angle. Also, relative tothe latter type, it was proposed that the louvers initially be bent toan angle equal to the final cutting angle less the clearance angle, thatthe outer edges of the louvers or slats then be fiat-groundsimultaneously in a plane parallel to the'plane of th blank, and thatthe louver be subsequently bent by an amount equal to the clearanceangle to complete the teeth. All of these proposed methods are directedto the formation of cutting teeth as such and involve transferring theblank from a cutting and bending die to a grinder, or fromdie-to-grinder-to-die, which is highly inconvenient and inefficient andadds considerably to the cost of the resultant product. Also, thecutting teeth in these prior art files, due to the fact that they areproduced simply by grinding, are short lived in comparison to thecutting edges of the conventional solid type files wherein the edges arechiseled-up from the face of a solid blank. Since this latter type oftile is produced economically and has a relatively long service life,sheet metal files have failed to attain a measurable degree ofcommercial success even though they afford excellent chip clearance andare not subject to clogging.

Recently, a further proposal has been made in the art to form a sheetmetal file blade in its entirety in a slat or louver cutting and bendingdie. According to this proposal, a single die element is employed to cutthrough the sheet metal blank at an angle to the plane thereof that isequal to the complement of the sum of the ultimate desired clearanceangle and the ultimate desired face angle of the resulting tooth, and tobend the tooth or louver, as part of a single cutting and bendingoperation, from the plane of the blank by an angle equal to the saidclearance angle. The angles recommended in practice of this proposal areto cut the blank at an angle of 60 degrees relative to the plane thereofand to bend each slat or louver as it is defined to an angle of 25degrees relative to the plane of the blank, thereby to define a toothhaving a clearance angle of 25 degrees, a cutting angle of 85 de-3,d77,l2fi Patented Fold. 12, 1963 grees and a face angle of 5 degrees,the face of the tooth comprising the frontal edge of the louver.However, when this proposal is practiced in the manner outlined, a sharpcutting edge is not formed on the slats or louvers, due apparently tothe die rounding off the corner defining the outer and alleged cuttingedge of each tooth, and the proposed apparatus therefore does not on itsface produce an effective tool.

The object of the present invention is to provide improved, highlyeiticient, practical and economical apparatus for making a sheet metalfile in its entirety in a die.

A more specific object of the invention is the provision of improvedapparatus for making sheet metal files characterized by die means forthrowing-up sharp burrs on a sheet metal blank at spaced intervalsthereon, and separate die means for bending the slats or louvers definedbetween adjacent burrs relative to the plane of the blank to such angleas to constitute each burr a cutting edge and to open up chip clearanceslots between the slats.

Gther objects and advantages of the invention will become apparent inthe following detailed description.

Now, in order to acquaint those skilled in the art with the manner ofmaking and using our improved apparatus for making sheet metal files, weshall describe, in connection with the accompanying drawings, preferredembodiments of the apparatus for making the files, and preferredembodiments of the files produced by use of the apparatus.

In the drawings, wherein like reference numerals indicate like parts:

FZGURE l is a side elevation of the preferred apparatus of ourinvention;

FIGURE 2 is a fragmentary view of the apparatus, the View being takensubstantially on line 22 of FIGURE 1 and showing the lower die part inplan;

FlGURES 3 and 3A are, respectively, a fragmentary plan view and across-section of one embodiment of the files produced by our apparatus;

FlGURES 4 and 4A are, respectively, a fragmentary plan view and across-section of a second embodiment of the files;

FEGURE 5 is a fragmentary perspective View of the cut ting dies employedin producing the file of FIGURE 4;

FIGURE 6 is a fragmentary perspective view of the cutting dies employedin producing the tile or" FlGURE 3;

FIGURE 7 is a fragmentary vertical section of the die members employedin the production of the file of FIG- URE 4, the view being on anenlarged scale and illustrating in vertical longitudinal section thefile produced by the dies;

FlGURE 8 is a fragmentary vertical section of the die members employedin the production of the file of FIG- URE 3, the view illustrating invertical longitudinal s'ec-' tion the file produced by the dies;

FIGURE 9 is an enlarged fragmentaly illustration of one cuttinginstrumentality as produced by the dies of FEGURES 7 and 8;

FIGURE 10 is a fragmentary vertical section, similar to FIGURE 8, of thedie members employed in the production of a modification of the file ofFIGURE 3, the View illustrating in vertical longitudinal section themodilied file produced by the dies; and

FlGURE' 11 is an enlarged illustration of one cutting 'instrurnentalityas produced by the dies of FIGURE 10.

Referring first to FIGURES 4, 4A, 7 and 9, the overall object of thisinvention is to provide improved apparatus for making a sheet metal filecomprising a generally planar body portion it), from which a pluralityof spaced parallel louvers or slats 12 are bent to form chip 7 clearanceslots M between the slats, each slat or louver having at its outermostedge a sharp upstanding burr 16 constituting the cutting edge of thefile. For purposes of rigidity, each slat orlouver 12 is interrupted toprovide at least one reinforcing land ldalong the length thereof. Theparticular formation of each louver is not especially critical accordingto the present invention, since we are not concerned with formation of acutting tooth in the strict sense, but simply with the provision of thesharp upstanding burrs 16 and the clearance slots 14 there-between. Tofacilitate the cutting action of the file, we prefer to form the slatsor louvers at an inclination to the longitudinal axis of the blank,suitably an inclination of about 20 to 25 degrees.

As best shown in FIGURES 9 and 11, the form of louver we prefer is bentto an angle (which would, in the art of toothed cutters, be called theclearance angle) of from about 20 degrees to about 40 degrees, dependingupon the form, or angle of formation, of the burrs 16. The upstandingburr should project generally normal to the plane of the body and isformed as a continuation of the outer portion of the frontal face 20 ofthe louver. This face projects from the body 14) of the file at an anglewhich should, in the terminology applied to conventional toothedcutters, be called the cutting angle. However, the cutting angle of ourlouver, instead of being an acute angle as is required in the art oftoothed cutters, is an obtuse angle, and moreover, is considerably inexcess of 90 degrees. Specifically, we prefer that this angle be fromabout 105 to about 125 degrees, again depending upon the specificformation of the burr. In the preferred embodiment, the defined cuttingangle results in a negative rake angle of from about 15 degrees to about35 degrees, as opposed to the positive face angle provided on toothedcutters.

Thelou-vers of our files are further distinguished from prior proposalsin the art in that the frontal face of each louver is'steppedor'irregular, including the outer portionabove described and a step orirregularity adjacent thereto.

To provide the louver as above described, we are concerned firstand-primarilywith formation of the sharp burr 16, since it is thecritical element of our file. We have discovered that the burr is formedmost effectively and efficiently by-cuttinginto but not through theblank and by exerting a combined holding, cutting and wedging action onthe blank.

Bearing this in mind, reference is now made to FIG- URE 7 for disclosureof one embodiment of our improved. apparatus for forming the burrs andmaking the filcs.- As illustrated, the apparatus employed includes apair of opposed die assemblies, indicated generally at 2.2 and24, eachincluding a cutter 26 and 28, respectively, and abending die 30 andi32,respectively. The lower die assembly 24 also includes a break 34disposed between the cutter 28 and. the bending die 32. The dieassemblies are adapted for relative movement in the vertical plane and.define therebetween a .path of blank movement that is inclined to thehorizontal. The angle of inclination is; not critical, but we prefer anangle of about 20-25 degrees, forproduction of the preferred form oflouver. As will be described, means are provided for incrementallyadvancing the sheet metal blank B step by step in an upward directionalong this path, a given portion of the blank first encountering the twocutters 26 and 28 and on the next succeeding increment of advancementencountering the bending dies 30 and 32.

Thecutters or cutting dies 26 and 28 each include a cutting edge, whichedges are offset slightly from one another in the plane of the blank.Each edge constitutes the line of intersection of a pair of surfaces 36and 33 which converge toward said edge from opposite sides of a verticalline intersecting the edge. The adjacent surfaces 36-36 of the twocutters form relatively low angles of inclination to the plane of theblank and the opposite surfaces SIS-38 thereof form relatively highangles of inclination to the blank. We prefer that thesurface 36 form anangle of about 30 degrees to the vertical, and that the surface 38 forman angle of about 15 degrees to the vertical. In particular, we preferthat the surface 33 define an angle relative to the plane of theiblankthat is greater than degrees, so that this surface will have reliefrelative to the blank. However, due to the inclination of the blank, asthe die assemblies are closed on the blank and the cutting edges cutinto the same, the surface 38 of each die presses into positiveengagement with the respective surface of the blank to force a sharpbu-rr upwardly from the surface, as indicated at 16 in FIGURE 7. Thisforcing action is enhanced by the fact that each cutting die serves toanchor the blank for the other cutter so that there is no adverserelative movement or slipping of the.

blank relative to the dies. To assure attainment of this anchoringfunction, the die assemblies are bottomed or stopped short of cuttingthrough the blank.

While the anchoring and burr raising functions as above described aretaking place, the adjacent surfaces 3636 of the two cutters furtherenhance both functions, and in particular contribute to the formation ofa significant, and exceedingly sharp and durable burr. Specifically, asthe die assemblies close on the blank, each surface 36 exerts, adjacentthe respective surface of the blank, a wedging force on the portion ofthe blank engaged thereby, which wedging force is opposed to the abovedescribed burr raising force and causes, we believe, a localizedshearing action adjacent the respective surface of the blank that causesthe said surface portion to be drawn forcibly against the face 38 of therespective cutter, thereby to assure formation of the respective burr.

Consequently, as the die assemblies are bottomed, the two cutters 26 and28 have raised burrs at the outer edges and have formed the inner andouter face portions of what will subsequently become the trailing faceof one louver and the frontal face of the next adjacent louver. Whenbottomed, the cutters have not cut through the blank,- as is clearlyillustrated in FIGURE 7, and the said two faces of adjacent louvers arejoined by a thin intervening portion adjacent the center of the blank.

To sever the said intervening portion between the adjacent louvers andto bend each louver (as defined between adjacent burrs on the same sideof the blank) to an appropriate angle relative to the plane of theblank, the die assemblies are separated, the blank advanced one step,and the die assemblies again closed on the blank. As the die assembliescommence to close, the portion of the blank that was worked on by thecutters in the immediately preceding step is rested on the brcakS twiththe burr 16 on the lower surface of the blank'to the forward side of thebreak and the burr 16 on the upper surface of the blank to the rearwardside of the working edge of the break. As shown, the cutter 26 isrelieved at the portion thereof overlying the break so as not to engagethe upper burr 16. As the die assemblies close, the bending die 30 firstengages the portion ofthe upper surface of the blank forwardly of theburr 16 last formed on said surface and forces the same downwardlyrelative to the supporting surface provided by the break 34, whereuponthe blank is caused to be sheared at its weakest point, i.e., the saidcentral portion thereof intervening between the said faces of adjacentlouvers, the shearing action producing the above described step orirregularity in the face. This shearing action takes place at a locationspaced from the burrs so that there is no danger that the burrs will berounded off or otherwise flattened or dulled as a consequence of thebending operation. At substantially the same time as the trailing edgeof one louver is severed from the frontal face of the next adjacentlouver, the forward end of the lower surface of the louver now beingworked upon is engaged by the bending die 32 whereupon the dies 39 and32 cooperate in bending the slat or louver to an angular positionrelative to the plane of the blank,

the shearing and bending steps causing the chip clearance slots 1 to beopened up between adjacent burrs.

Relative to the combined holding, wedging and cutting or scoring of theblank for the purpose of throwin -up the burr 16, it is to be observedthat the bending die 30 contests the blank and is forced into firmengagement therewith before the cutting or scoring die 26 contacts theblank. By virtue of this relationship, together with the cooperationbetween the inclined generally complementary faces of the bending die 3tand the louver being formed (which faces are opposed to the burr formingface of the die as the bending die 34 assists the cutters 25 and 28 andthe faces 36-36 thereof in positively restraining the blank againstslippage to the left or in the reverse direction, whereby the faces 3333of the dies 26 and 2.3 positively force up sharp burrs from the surfacesof the stationary blank.

In the preferred construction of the die assemblies, the adjacent facesd s -fit of the bending dies 3d and 32 are suitably formed at an angleor" about 60 degrees to the horizontal. To avoid damage to the sharpburrs l6 during the bending step, the bending dies may be relieved orrecessed in a known manner in the area adjacent the burrs, but we prefersimply to bottom or stop the die assemblies 22 and 2 before the bendingdies 31 and 32 bottom on or engage flush against the full surface of thelouver.

The bending step completes the formation of each louver to the formillustrated fragmentarily in FIGURE 9, so that upon separation of thedie assemblies and incremental advance of the blank, the louver issuingfrom the die assemblies is a complete and highly efficient cuttinginstrumentality for the filing and/ or planing of materials ranging fromsoft wood to metals having a Rockwell hardness of up to about 35.

The die asse. italics are operated in timed sequence with the means forincrementally advancing the blank, thereby to form spaced parallellouvers throughout substantially the full length of the blank, bodyportions 1t! being left at both ends to facilitate mounting of the fileon a holder or the like. After the file has been formed in the mannerdescribed, it is preferably hardened, in any conventional or desiredmanner, to afford a tool of exceedingly long life.

In the embodiment of the file above described, the louvers are allidentical and each include a single land or tie connection 18, whichlands are aligned and continuous longitudinally of the blank. The landsor ties are accommodated by forming aligned recesses 42 at the centralportion of the cutting edges of the cutters 26 and 23, see FIGURE 5, andby providing similar recesses in the same location on the bending dies.Since the louvers or slats are all identical, only a sin le pair ofcutters and a single pair of bending dies are required to form the file.

Referring now to FIGURES 3, 3A, 6 and 8, we have illustrated a file thatdiffers from the embodiment above described in that the same is ofchannel form in crosssection and is provided with staggered orinterrupted rigid ifying lands or tie connections between the louvers.1e specific cross-sectional form of each louver, including its burr 16is, however, the same as illustrated in FIGURE 9. As shown in FiGURE 3,the body of the file includes a planar portion tile and dependingmarginal edge portions 11a. The louvers extend from edge portion to edgeportion and are generally of two types, 12:: and 1%, respectively, thelouvers 12! each including three lands or ties lfia that are aligned inrespective sets longitudinally of the file, and the louvers 1221 eachincluding three lands or ties 18b that are aligned in respective setslongitudinally of the file and staggered relative to the lands 18a.

To form the two different types of louvers, as opposed to the singletype produced by the die assemblies of FIGURES 5 and 7, it is simplynecessary, in general terms, to double the die means and the length ofthe incremental step of the blank advancing means. Specifically, asshown in FIGURE 8, the die assemblies 22:: and

24:; are provided with two pairs of cooperable cutters Zea-Zita and26b2$b, and with two pairs of cooperable bending dies 3tia-32a and3tlb32b. The die 32a, in addition to its louver bending function, servesas a break for the die set Shiv-32b, and the lower die assembly includesa break 34:: for the die set Elba-32a. As shown in FlGURE 6, the cutters2fib--28l2 are provided With aligned recesses 42!) which accommodateretention of the lands 18b, and the cutters Zora-23a are provided withaligned recesses 42a which are staggered relative to the recesses 42band accommodate retention of the lands the. By virtue of thisconstruction, each time the dies are closed on a blank, the four cuttingdies form the burrs lid on one each of the two types of louvers, and thefour bending dies bend up one louver of each type, in the same manner asdescribed in conjunction with FIGURE 7. Upon each operation thereof, theadvancing means advances the blank by a distance equal to two louvers,thereby to cause formation of two complete louvers on each cycle ofoperation. Obviously, if desired, the file of FIGURE 4 could also beformed two louvers at a time with die assemblies similar to thoseillustrated in FIGURE 8.

The double acting die assemblies illustrated in FIG- URES 5 through 8are ideal for the formation of a file of the cross-sectionalconfiguration illustrated in FIGURE 4A, wherein the louvers are fullyexposed at both faces of the file, for the reason that cutting edges arethen formed on both faces whereby either face of the tile may be usedfor performance of useful Work. With a file of channel cross-section, asillustrated in FIGURE 3A, or of half-round form, however, the edges ofthe louvers extending between the side wall portions of the file are notgenerally accessible for performance of work and there is, therefore, noneed to form cutting edges to the interior side of the channel or thelike. Consequently ie means of the type shown in FIGURE 10 are preferredfor the manufacturing of files of such cross-sectional configuration,and for files which are to have only a single working face.

For purposes of illustration, we have shown in FIG- URE 10 double indexdie means, i.e., means for forming two louvers at a time, but it is tobe understood as the description proceeds that this type of die meansmay be embodied in single index or other multiple index forms asdesired. As shown, the upper die assembly 22): is very similar to theupper die assembly shown in FIGURE 8, the instant assembly including apair of scoring or cutting dies 26x and 26y and a pair of severing and.bending dies 31%;: and 3th. The lower die assembly 24 x, like that shownin FIGURE 8, includes bending dies 32x and 32y cooperable respectivelywith the dies 30x and Filly, the die piece 322: also serving as a breakfor the die set 3t'ly32y. In this case, however, the lower cutting orscoring dies and the break are replaced by a unitary anvil 45 whichunderlies the scoring dies 2dr and. 26y and has an upper surface 4'7that is inclined at the same angle to the horizontal as the path ofblank movement, whereby the body portion of the blank rests flat againstsaid anvil surface during the cutting or scoring operation. The upperedge portion of the anvil 45 constitutes a break for the die set3t3x32x, and the severing and bending dies 3% and Edy in this embodimentare sharply pointed, rather than being relieved as are the dies 3th; and36b in FIGURE 8.

in use of the die means of FIGURE 10, as the upper die assembly 22x isclosed on the lower assembly 24x, the bending dies 3th: and 3G firstengage the blank B substantially simultaneously and are forced intofirmly retentive engagement therewith. Subsequently, the scoring dies2dr and 26y substantially simultaneously engage and are forced into theblank to raise sharp burrs 16x and tidy from the surface of the blank.During the burr raisin operation, the blank is held against longitudinal movement, especially in the reverse direction, i.e.,

to the left, by virtue of the firmly retentive engagement of the dies30x and 30y with the blank. Since the inclined faces'dilx and 49y of thedies 30x and 30y are opposed to the burr raising faces 33x and 33y ofthe dies 26x and 26y, the bending dies perform an ideal holdingfunction. At the same time, the faces 36x and 36y of the dies 26x and 25exert wedging forces on the blank opposed to the burr raising forces,thereby to insure formation of significant burrs. As will be noted, thescoring dies are forced into but not through the blank.

The upper die assembly is then moved away from the lower assembly andthe blank advanced an increment equal to two louvers, whereafter theupper die is closed on the lower die. As the bending dies 30): and 30yengage the blank, the same enter two adjacent scores previously made bythe scoring dies just forwardly of the respective burrs and sever fromthe blank a pair of louvers, which they thereafter bend to anappropriate inclination relative to the blank; Consequently, each timethe dies separate and the blank is advanced, two finished louvers issuefrom the apparatus.

The completed louver formed by the apparatus of FIGURE IO is illustratedin FIGURE 11, from which it will be noted that the louver ischaracterized by the same distinctive features as the louver shown inFIGURE 9. For purposes of comparison, the same reference numerals asemployed in FIGURE 9-are used in FIGURE 11 with the suffix x. Thedifferences between the two louvers are essentially two; first, that thelouver of FIGURE 11 has a burr only at its outer forward edge, whereasthe louver of FIGURE 9 (see FIGURES 7 and 8 also) has burrs both at-itsouter forward edge and lower rearward edge, and second, that theinterruption or step in the frontal face of the louver of FIGURE 11 isadjacent the inner edge thereof, whereas the stepis intermediate theedges ofthe face in the louver of FIGURE 9. The clearance and rakeangles .of both louvers fall within the ranges previously stated herein,and the sharp burr in each case is disposed outermost and projectsgenerally normal to the plane of the blank, the louvers providingtherebetween large chip clearance spaces.

In'the presently preferred embodiment thereof, the louver has aclearance angle of about 25 degrees and a negative rake angle ofapproximately 19 degrees. With the apparatus illustrated, a desirableWorking range is a clearance angle of from 25 degrees to 30 degrees anda negative rake angle from 19 degrees to 24 degrees. In its passagethrough the dies, the blank is preferably inclined at about 21 degreesto the horizontal (considering the upper die assembly to reciprocatevertically) and the inclination of the die piece faces to vertical ispreferably asfollows: the burr raising face (38) of the scoring die (228) 15 degrees; the wedge surface (3-6) of the scoring die (262S) 30degrees; and the bending surface (4t?) of the bending dies (39-62) 30degrees; the bending die sets having sufficient clearance between thedies thereof when the die assemblies are bottomed to bend the louver toan inclination of 25-30 degrees to the plane of the blank, 46-51 degreesto horizontal, whereby the bending dies are held out of engagement withthe sharp burrs.

In working on a blank with the illustrated die means, the bending dieson the first stroke of the upper die engage the lead end portion of theblank and form full or partial louvers that are not provided with sharpburrs, since this portion of the blank was not engaged by the scoringdies. Consequently, with the die means of FIG- URE 10, as shown therein,a partial louver and two full louvers are formed that do not have sharpedges. The die means of FIGURE 8 perform in like manner. With the diemeans of FIGURE 7, one partial louver and one full louver are absent thesharp burr. This is simply mentioned for purposes of completing thedescription of the resultsproduced by the die means, since in a fileblade about 10 inches long having approximately 85 full louvers therein,the absence of a cutting edge on one or two of the louvers at the leadend of the file is of no practical consequence. Also, at the trailingend of the file, the double index die means of FIGURES 8 and 10 willleave two score marks on the blank as shown in FIGURE 3, and the singleindex die means of FIGURE 7 will leave one score mark as shown in FIGURE4.

Referring now to FIGURES l and 2, we have illustrated apparatus suitablefor actuating the die assemblies of FIG- URES 7, 8, and 10 and foradvancing the blank relative to the dies. The apparatus comprises aconventional punch press having a stationary bed 5ft and a'movable head52 mounted for vertical reciprocation on upright guide bars 54 having afixed mounting relative to the bed 5t Fixedly mounted on the bed St) isthe lower die assembly 24, while the upper die assembly 22 is carried bythe head 52 for vertical reciprocation relative to the assembly 2- thetwo assemblies defining therebetween an inclined path of advancement forthe blank. Mounted at the same inclination on the bed 58 is a generallyU- shaped frame 56 between the legs of which an advancing screw 5% isjournalled.

The screw 58 includes a drive shaft extending through the lower leg ofthe U-shaped frame and is equipped at its lower end with an intermittentdrive means 6%), which may suitably be manually actuated. In theillustrated structure, the means 68 comprises'a ratchet member 62 fixedto the screw and a pawl 64 journalled on the screw, the pawl beingarcuately movable between predetermined end positions andhaving aone-way driving connection with the ratchet, thereby to rotate the screwa predetermined amount inadvancing direction upon each actuationthereof.

Mounted on the frame 56 for sliding movement therealong, preferably in adove-tailed assembly, is an advancing member '66 which includes a screwfollower 68 normally engaging the screw 58, cam actuated means 7% formoving the follower 53 into and out of cooperative engagement with thescrew, a guiding and abutment member 72 for engaging in and against thetrailing end of the sheetmetal blank for advancing it between the diesand a spring biased hold-down 74 cooperating with the abutment memberand the blank for retaining the blank on said member.

In use, the means 7th is first actuated to release the follower 68' fromthe screw 58, whereupon the member 66 is manually slid downwardly-on theframe 56 to its rearwardmost position, the follower 68 then being movedback into cooperative engagement with the screw. The hold-down '74 isreleased momentarily and a blank slipped into place on the member 72,whereafter the hold-down is engaged with the blank. The press may thenbe set into operation, and each time the head moves upwardly away fromthe bed, the pawl 64 is actuated to cause the member 66 and the blank tobe advanced one step relative to the die assembly. When the file hasbeen formed, the member 65 is again slid rearwardly on the frame,whereupon the finished file may be removed and a new blank put in placefor repetition of the steps described.

Thus, it is to be appreciated that the file is formed in a highlyconvenient, economical and practical manner, by apparatus andperformance of a method that afford substantial improvements over theproposals of the prior art, and that result in a distinctively improvedsheet metal file of exceedingly long service life.

By virtue of the described apparatus, each louver presents a sharp burrwhich extends generally normal to the plane of the body and constitutesan effective and efficient cutting edge. With the dies of FIGURES 7 and8, either side of the resultant file may be utilized for performing afiling or planing function. Moreover, by turning the louvers to aslightly higher angle relative to the plane of the file body thanindicated hereinbefore, each burr can be rendered capable of performinguseful work in both directions of reciprocation of the file. We find,however, that generally the most useful work is performed by the louverform illustrated in FIGURE 11 upon movement of the file to the right asthe same is viewed in said figure.

From the foregoing, it is to be appreciated that the objects andadvantages of the present invention have all been shown to be obtainedin a highly convenient, economical and practical manner.

While we have shown and described what we regard to be the preferredembodiments of our apparatus for making sheet metal files, it is to beappreciated that various changes, rearrangements, and modifications maybe made in these embodiments without departing from the scope of theinvention as defined by the appended claims.

We claim:

1. In apparatus for making sheet metal files including a pair ofrelatively movable opposed die pieces, means for moving the die piecestoward and away from one another, and means for advancing a sheet metalblank between the die pieces in a given path, the improvement comprisinga cutting die and a bending die carried by one of said die pieces, andcooperating dies carried by the other die piece, said bending dieextending forwardly of said cutting die in the direction of movementthereof, which is transverse to the path of blank movement, for engagingand retaining the blank against longitudinal movement prior toengagement therewith of said cutting die, said cutting die including acutting edge and a surface adjacent thereto for cutting into and raisinga sharp burr from the blank while the blank is retained stationary bysaid bending die, said bending die being disposed behind said cuttingdie in the direction of blank advancement and including a surfaceinclined relative to the path of blank movement for bending from theplane of the blank the slats formed between adjacent cuts in the blank.

2. In apparatus for making sheet metal files including a pair ofrelatively movable opposed die pieces, means for moving the die piecestoward and away from one another, and means for advancing a sheet metalblank between the die pieces in a path inclined to the direction ofrelative movement of said die pieces, the improvement comprising acutter carried by at least one of said die pieces and including acutting edge and a surface to the forward side of said edge relative tothe direction of blank advancement that extends generally normal to thepath of blank movement, and a bending die carried by each said diepieces rearwardly of said cutter relative to the direction of blankadvancement, said bending dies including a face to the rearward sidethereof that is inclined relative to the path of blank movement, saidbending dies leading said cutter in the direction of movement of saidone die piece, which is transverse to the path of blank movement, saidadvancing means advancing the blank by a distance equal to the distancebe tween the leading edges of said cutter and said bending dies aftereach operation of said relatively movable die piece whereby, upon eachclosing of said die pieces, said bending dies first engage the blank toretain the same against movement and bend a slat from the plane of theblank and said cutter cuts into the stationary blank and said surfacethereof raises a sharp burr from the blank, which burr will constitutethe outer forward edge of a slat subsequently bent from the plane oftheblank by said bending dies.

3. In apparatus for making sheet metal files and the like including apair of relatively movable opposed die pieces, means for moving the diepieces toward and away from one another and means for advancing a sheetmetal blank between the die pieces in a given path inclined to thedirection of relative movement of the die pieces, the improvementcomprising a pair of opposed cutters associated respectively with saiddie pieces and including cutting edges offset from one another in adirection considered longitudinally of the direction of the path ofblank movement thereof, the adjacent sides of said cutters formingrelatively low angle inclined wedge surfaces relative to the path ofblank movement and the other sides thereof forming relatively highangles relative to said path, the said sides of each cutter convergingtoward the cutting edge of the respective cutter from opposite sides ofa line extending through said edge parallel to the direction of relativemovement of said die pieces whereby, as said cutters cut into a sheetmetal blank, the said adjacent sides exert wedge forces on the oppositesurface portions of the blank in opposite directions in the plane of theblank and the said other sides thereof each exert a force on the blankopposed to the said wedging action of the respective cutter to raise asharp burr from the respective surface of the blank.

4. In apparatus for making sheet metal files and the like including apair of relatively movable opposed die pieces, means for moving the diepieces toward and away from one another and means for advancing a sheetmetal blank between the die pieces in a given path, the improvementcomprising a cutter carried by one of said die pieces and including acutting edge, a first surface forwardly of said edge relative to thedirection of blank advancement that extends generally normal to the pathof blank advancement and a second surface to the rearward side or" saidedge forming an inclined wedge surface relative to the path of blankmovement, whereby, as the cutter cuts into a sheet metal blank, the saidwedge surface thereof exerts a force on the blank in the direction ofblank advancement to cause said first surface thereof to raise a sharpburr from the surface of the blank, the said advancing means advancingthe blank along said path step by step in timed relation to the relativemovements of said die pieces to cause spaced parallel burrs to be raisedfrom said surface of the blank, and a bending die carried by each saiddie pieces to the rearward side of said cutter for engaging the slatsdefined between adjacent burrs and bending said slats to an inclinedposition relative to the plane of the blank to open up chip clearancespaces between adjacent burrs and dispose said burrs outermost, said.bending dies leading said cutter in their approach to the path of blankmovement as directed by relative movement of said die pieces forengaging the blank and retaining the same stationary prior to and duringcutting thereof.

5. In apparatus for making sheet metal files and the like including apair of relatively movable opposed die pieces, means for moving the diepieces toward and away from one another and means for advancing a sheetmetal blank between the die pieces in a given path inclined to thedirection of relative movement of the die pieces, the improvementcomprising a cutter carried by one of said die pieces and including acutting edge, a surface to the forward side of said edge relative to thedirection of blank advancement which surface extends generally normal tothe path of blank movement, and a surface to the rearward side of saidedge forming a relatively low angle inclined wedge surface relative tothe path of blank movement, the said surfaces of said cutter convergingtoward its cutting edge from opposite sides of a line extending throughsaid edge parallel to the direction of relative movement of said diepieces, whereby, as said cutter cuts into a sheet metal blank, the saidwedge surface thereof exerts a wedge force in the plane of the blank inthe direction of blank advancement and said normal surface thereofexerts a force on the blank opposed to the said wedging force to raise asharp burr from the surface of the blank, the said advancing meansadvancing the blank along said path step by step in timed relation tothe relative movements of said die pieces to cause spaced parallel burrsto be raised from the surface of the blank, said cutter in the closedposition of the die pieces extending only partially into said path,whereby the same cuts into but not through the blank, and a pair ofopposed bending dies associated respectively with said die pieces inpredetermined relation to said cutters for engaging the slats definedbetween adjacent previously formed burrs, said bending dies forming anacute angle relative to said path of blank movement and having clearancein the closed position of the die pieces relative to the said burrs,said bending dies bending said slats to an inclined position relative tothe plane of the blank without damage to said burrs and severing therespective slats from the blank along the respective cuts to open upchip clearance spaces between adjacent burrs and dispose said burrsoutermost, said bending dies leading said cutter in the direction ofrelative movement to said die pieces to- Ward the path of blank movementwhereby said bending dies engage the blank before said cutter to retainthe blank stationary during cutting thereof to assist in accomplishmentof the burr raising function of said cutter.

6. In apparatus for making sheet metal files including a pair ofrelatively movable opposed die pieces, means for moving the die piecestoward and away from one another, and means for advancing a sheet metalblank between the die pieces in a given path, the improvement comprisinga cutting die and a bending die carried by one of said die pieces and ananvil and a bending die carried by the other die piece, said cutting diebeing supported in vertical alignment with said anvil, and the bendingdies extending forwardly of said cutting die and anvil in the directionof their relative movement which is transverse to the path of blankmovement for engaging and retaining the blank against longitudinalmovement prior to engagement therewith of said cutting die, said cuttingdie including a cutting edge and a surface adjacent thereto for cuttinginto and raising a sharp burr from the blank while the blank is retainedstationary by said bending dies, said bending dies being disposed behindsaid cut ting die in the direction of blank advancement and including asurface inclined relative to the path of blank movement for bending theslats formed between adjacent cuts in the blank from the plane of theblank.

7. In apparatus for making sheet metal files and the like including apair of relatively movable opposed die pieces, means for moving the diepieces toward and away from one another and means for advancing asheet-metal blank between the die pieces in a given inclined path, theimprovement comprising an inclined anvil carried by one of said diepieces and a cutter carried by the other of said die pieces in verticalalignment therewith, the cutter including a cutting edge, a firstsurface forwardly of said edge relative to the direction of blankadvancement that extends generally normal to the path of blankadvancement and a second surface to the rearward side ofsaid edgeforming an inclined wedge surface relative to the path of blankmovement, whereby, as the cutter cuts-into a sheet metal blank supportedon the inclined anvil, the said wedge surface thereof exerts a force onthe blank in the direction of blank advancement to cause said firstsurface thereof to raise a sharp burr from the surface of the blankWithout cutting through said surface, the said advancing means advancingthe blank along said path step by step in timed relation to the relativemovements of said die pieces to cause spaced parallel burrs to be raisedfrom each surface of the blanks, said anvil having an upper edge surfaceconstituting a break, and said die pieces each further having a bendingdie to the rearward side of said 'break and cutter for engaging theslats defined between the adjacent burrs, and bending said slats pastsaid break to sever an edge thereof from the sheet metal and todispose'the slats in an inclined position relative to the plane of theblank so as to open up chip clearance spaces between adjacent burrs anddispose said burrs outermost, said bending dies leading said cutter andanvil in their approach to the path of blank move- References Cited inthe file of this patent FOREIGN PATENTS 457,841 P121166 'July 3, 19131,088,345 France Sept. 8, 1954 799,091 Great Britain July 30, 1958

1. IN APPARATUS FOR MAKING SHEET METAL FILES INCLUDING A PAIR OFRELATIVELY MOVABLE OPPOSED DIE PIECES, MEANS FOR MOVING THE DIE PIECESTOWARD AND AWAY FROM ONE ANOTHER, AND MEANS FOR ADVANCING A SHEET METALBLANK BETWEEN THE DIE PIECES IN A GIVEN PATH, THE IMPROVEMENT COMPRISINGA CUTTING DIE AND A BENDING DIE CARRIED BY ONE OF SAID DIE PIECES, ANDCOOPERATING DIES CARRIED BY THE OTHER DIE PIECE, SAID BENDING DIEEXTENDING FORWARDLY OF SAID CUTTING DIE IN THE DIRECTION OF MOVEMENTTHEREOF, WHICH IS TRANSVERSE TO THE PATH OF BLANK MOVEMENT, FOR ENGAGINGAND RETAINING THE BLANK AGAINST LONGITUDINAL MOVEMENT PRIOR TOENGAGEMENT THEREWITH OF SAID CUTTING DIE, SAID CUTTING DIE INCLUDING ACUTTING EDGE AND SURFACE ADJACENT THERETO FOR CUTTING INTO AND RAISING ASHARP BURR FROM THE BLANK WHILE THE BLANK IS RETAINED STATIONARY BY SAIDBENDING DIE, SAID BENDING DIE BEING DISPOSED BEHIND SAID CUTTING DIE INTHE DIRECTION OF BLANK ADVANCEMENT AND INCLUDING A SURFACE INCLINEDRELATIVE TO THE PATH OF BLANK MOVEMENT FOR BENDING FROM THE PLANE OF THEBLANK THE SLATS FORMED BETWEEN ADJACENT CUTS IN THE BLANK.